NIKE Lightweight Running Hydration Pack contains (55%) nylon (15%) polyester (10%) eva (7%) pe (5%) pu materials. This hydration pack includes a dual-adjustable padded belt that is designed to stay in place and help prevent uncomfortable rubbing and chafing. It also holds an iPod and Nike + transmitter and routes the cords to keep them out of your way. This product features a storage compartment, I.D. tag for personalization and identification, and swoosh design trademark.